Retinopathy and RAAS activation: Results from the Canadian study of longevity in type 1 diabetes

Diabetic Retinopathy (diabetic eye disease) is the most common cause of preventable blindness in adults, and the most common vascular complication in people with diabetes. Researchers know that high blood sugar levels can damage the eyes through a system called renin-angiotensin aldosterone system (RAAS). While there are treatments to block RAAS, this study wanted to understand if RAAS is still active in the eye after patients develop diabetic eye disease and after many years with type 1 diabetes. They also wanted to know if RAAS causes damage in other parts of the body. They looked at participants from the Canadian Study of Longevity in Type 1 Diabetes, who had all lived with T1D for more than 50 years. They found that those people with the most advanced eye disease had the highest levels of RAAS activity. Patients with high RAAS activity also had more stiffening of the arteries behind the eye. Those in the study with persistent diabetic retinopathy also had worse nerve function and higher risk for plaque buildup in the arteries. This knowledge is helpful because it shows that the use of RAAS blocking drugs in people with long-standing T1D is beneficial and opens up the opportunity to study other areas of connection between RAAS and the body.